Our results showed that zonulin release was markedly reduced in NEC rat pups after pretreatment with bifidobacterium and it was positively related to intestinal permeability, which revealed that zonulin protein might involve in the protective mechanisms of bifidobacterium on intestinal barrier function of NEC by regulating intestinal permeability and modulating intercellular TJ. Here, HP is linked to necrotizing enterocolitis.